Heliodent ds

Detailed FDG-PET/CT acquisition protocols have been reported previously [14 (link), 15 (link)]. In brief, fasting patients with a blood glucose serum concentration below 12 mmol/l were injected with a standardised dose of 18F-FDG, according to our institution’s protocol. After the injection, the patients rested for one hour in supine position in a warm environment. Scanning was performed using integrated PET/CT systems (Discovery MI PET/CT or Discovery PET/CT 690, GE Healthcare, Waukesha, WI, USA).
OPTs were generated in a standing position, with the head oriented to the Frankfurt plane, using a Cranex 3D (Soredex, KaVo, Biberach, Germany). Periapical radiographs were generated using a Heliodent DS (Dentsply-Sirona, Bensheim, Germany) intraoral X-ray, operating at 60 kV and 7 mA. The parallel technique was used with a focus-patient distance of approximately 21 cm.

For digital bitewing radiography with a sensor (XIOSPLUS-Sensor 31.3 × 44.5 × 6.7 mm; Dentsply Sirona, Bensheim, Germany), a commercial intraoral X-ray unit (Heliodent DS, Dentsply Sirona) was used. The exposure time was 0.06 s at a cathode voltage of 60 kV and a current of 7 mA.
The caries lesions were assessed according to Marthaler, describing four different caries stages: D1 outer and D2 inner half are limited to caries enamel lesions and D3 outer and D4 inner half describing caries dentinal lesions [47 (link)]. For better comparability of the bitewing radiography data to the other diagnostic methods, the classification of Marthaler was simplified. Sound areas without radiologically detectable caries lesions were scored using a numerical value (0). Caries enamel lesions were marked with numerical values (1) and caries dentinal lesions with numerical value (2). While the greatest caries progression per tooth was assessed for the evaluation of the occlusal lesions, both the mesio-proximal and disto-proximal surfaces could be examined for proximal caries lesions. The reason for assessing the occlusal lesion according to the greatest caries progression per tooth and not per surface is the two-dimensionality of the bitewing radiography.

All subjects were examined using a two-dimensional (2D) X-ray device (Orthopos S 2D; Dentsply Sirona, Charlotte, NC, USA). The exposure time for the OPT was set for 14.1 s with the following further settings: 63 kV, 8 mA, and FDP 91. Periapical radiographs were made with an intraoral X-ray unit (Heliodent DS; Dentsply Sirona, Charlotte, NC, USA) with an exposure time between 0.03 and 0.06 s depending on the examined tooth. Further settings were as follows: 60mA, 7 mA, and FDP 9-12. Image acquisition was performed using the paralleling technique in which the film is placed parallel to the long axis of the tooth.